Synthetic Electrocardiographic Monitor

12-Lead ECG & Additional Leads Simulator

Specification of graphical instrumentation, frontal and precordial lead systems, accessory leads, and instantaneous cardiac dipole vector calculation in MioAtlas.

View ECG with additional leads (add=1) Open in expanded view (exp=1)

1. Calibration, sampling rate, and millimeter grid

The signal rendering engine in MioAtlas generates the electrocardiographic tracing continuously at an internal update rate of 120 Hz on a GPU-accelerated HTML5 Canvas. To guarantee visual fidelity to standard clinical recording formats, the tracing projects onto a mathematical grid calibrated according to AHA/ACCF/HRS recommendations (Kligfield et al. 2007):

Paper speed 25 mm/s Each 1 mm small box equals 0.04 s (40 ms); each 5 mm large box equals 0.20 s (200 ms).

Voltage calibration 10 mm/mV Each 1 mm vertical small box represents 0.1 mV (100 µV); a standard 1 mV calibration pulse equals 10 mm.

Dynamic QT adaptation Fridericia formula QT interval recalculates instantaneously cycle-by-cycle using the cube root of R-R interval anchored to 390 ms at 72 bpm.

2. Standard 12-lead system and additional leads

The monitor simultaneously displays twelve conventional leads organized in the customary 4-column by 3-row layout with a continuous rhythm strip in lead II:

Frontal bipolar leads (I, II, III): Calculated as potential differences between limb electrodes according to Einthoven triangle.
Augmented frontal unipolar leads (aVR, aVL, aVF): Referenced to Goldberger central terminal exploring high lateral, rightward, and inferior planes.
Horizontal precordial leads (V1 to V6): Referenced to Wilson central terminal (WCT) with electrodes placed in anatomical pericardial intercostal spaces.

Accessory leads activated with parameter `add=1`

By adding parameter add=1 to the simulator URL, the monitor extends its coverage registering five complementary accessory leads:

These leads are essential to visualize transmural infarction extension to the posterior left ventricle (Wagner et al. 2009) and concomitant right ventricular involvement in proximal right coronary artery occlusions.

3. 3D vectors in thoracic space and dipole calculation

Unlike traditional flat-tracing monitors, MioAtlas computes at each temporal instant a three-dimensional cardiac dipole vector P(t) = (Px, Py, Pz) derived from the spatial sum of all active cellular elements in the myocardium.

Each physical lead is modeled as a unit lead vector L_i in the three-dimensional torso space (Frank 1956; Sovilj et al. 2013). Voltage recorded in lead i at instant t is computed via dot product between dipole vector and lead vector:

V_i(t) = P(t) \cdot L_i + V_baseline

In the 3D interface, the user can rotate, zoom, and visually inspect real-time orientation of the instantaneous cardiac vector projected onto frontal, horizontal, and sagittal planes.

4. Interactive display control parameters

You can directly control monitor behavior via the following deep linking parameters:

Parameter	Value	Technical effect on interface
`add`	`1`	Enables accessory leads V7–V9 and V3R–V4R in the lead panel.
`exp`	`1`	Opens monitor in full-screen / expanded mode for detailed analysis.
`vec`	`1` \| `0`	Shows or hides lead vectors drawn over the 3D model.
`op`	`15`–`100`	Myocardium opacity, to view conduction system through ventricular wall.

The complete parameter grammar documents remaining keys, accepted values, and defaults, including those altering simulated pathology (territory, evolutionary phase, coronary dominance, severity, and multivessel disease).